West Sussex · England
Crosspost Window Mastic
Window mastic for Crosspost, by sealant specialists with 20+ years’ experience. 180+ five-star Google reviews and a 4.9 rating.
- Gaps left after new windows were fitted
- Gaps between the frame and the inside reveal
- Cracked or shrunken mastic around the frame
Window mastic in Crosspost
From a single sill to a whole house of windows, the work is priced before anything is done. Just ring 0345 464 0079 or send us an email and tell us how many frames there are and how they’re reached for window mastic in Crosspost. Common call-outs are for cold air getting in at the frame edge and cracked or shrunken mastic around the frame, across patio & French doors, window sills and timber windows & doors.
Around Crosspost, many homes face open ground, so their windows and doors take the full weather. Exposed frames and sills lose their mastic sooner than sheltered ones.
We guarantee the work for a year. If there’s a problem with our work within the year, let us know and we will sort it.
- Where
- Crosspost (RH17)
- Region
- West Sussex
- Guarantee
- A year, on every job
- Quote
- A clear quote up front
- Phone
- 0345 464 0079
- Last updated
- 26 October 2026
Surface by surface
Aluminium frames
Aluminium needs a sealant that bonds to coated metal, and acetoxy silicones are not used, as they can attack some metals. We use a neutral-cure product.
Patio & French doors
Heavy door frames can move more than windows. The sealant must cope with it.
Should I try it myself first?
The biggest DIY mistake is sealing over old sealant. New silicone won’t bond to old, so it lifts and traps water and mould underneath. All the old material has to come out first.
What a professional job adds is preparation and the right product. Joints are cleaned back to sound surfaces and dried, and the sealant is chosen for how the joint moves and where it is, then guaranteed for a year.
Work for landlords, hotels and businesses
Housing providers, facilities teams and property managers book us too in Crosspost and across West Sussex. Several sites can be quoted together.
From a single let to a portfolio, you get the same standard of work: the old material taken out, careful preparation and a 12-month guarantee.
When to call us in Crosspost
Plenty of failed mastic was poorly applied in the first place. Sealant run over dust, wet brick or loose mortar didn’t grip properly, and it lets go sooner than it should.
Any of these means the joints need attention:
- Hard, cracked sealant around windows
- Sealant in the wrong colour for the frame
- Black, perished sealant on frames
- Gaps between the frame and the inside reveal
In the older streets around St Mary Magdalene's Church, frames set in older brick or stone need a sealant that suits the wall as well as the frame.
What to look for in a quote
- What preparation is included
- What product goes in the joint
- Whether they seal over old material or remove it
- What guarantee comes with the work
Your questions about window mastic in Crosspost
Do you cover Crosspost for window mastic?
Yes, Crosspost is within the area we cover. Our work covers London and the South East. Just ring 0345 464 0079 or drop us an email with a few details of the job.
Will you come out to Crosspost?
Yes, we do. Our work covers London and the South East, and smaller places are part of that. Longer journeys are simply planned in advance.
Can you do the inside joint as well?
Yes, we do both. Indoors, we seal between the frame and the plaster or reveal.
Can tenants book the work?
Yes. Check with your landlord; we can send the quote to them too.
Will resealing my frames help with draughts?
If the draught is coming in around the frame, yes. If it’s coming through the window seals, we’ll tell you.
Do the sealants smell?
Sometimes, a little. It fades as the sealant cures.
Do you remove the old sealant?
Yes. All of the old material is cut out and the joint cleaned before applying anything new.
Do you have sealant for grey or black windows?
Yes. White, brown, anthracite grey, black and clear sealants are all available, so the joint suits the frame.
Towns and villages near Crosspost
More services for Crosspost
Aftercare tips
To keep the joints looking good and working properly:
- Keep timber frames painted
- Air rooms to keep condensation down around windows
- Keep jet washers away from the mastic
- Walk round the house once a year and look at the joints
Most silicone sealants will not take paint, so if you are planning to paint the frames or walls, tell us beforehand. There are paintable sealants for joints that need it.
Water gets in quietly when mastic fails. Often the first sign is a damp patch inside or flaking paint on the reveal. Early resealing stops it reaching that point.
Crosspost homes and the weather
Rainfall in the South East is lower than in much of the UK, yet outdoor joints still have to be sealed dry, so jobs are booked with the weather in mind. Historic houses like Ockenden Manor (about 3.1 miles north-east) are a reminder that the area around Crosspost has older buildings as well as new. In older buildings, older timber frames in brick or stone need a different approach from a modern uPVC window.
Managing a site like Bolney CofE Primary School? Then the mastic around its windows and doors needs looking after like any other building’s. Letting a property close to Wivelsfield station? Then cracked frame mastic tends to show up as a draught or damp complaint, so it’s worth checking between lets.
Crosspost is about 4 miles north-west of Burgess Hill, in West Sussex. Every kind of property in Crosspost can book us for window mastic. Every job comes with our 12-month guarantee. Across West Sussex, we cover 371 places, Crosspost among them. We also work in Crawley, around 9 miles away.
Jobs for window mastic in RH17 works the same way as everywhere else we cover. Whether your property is on Cowfold Road and Chapel Road or a nearby road, we can help. Other places close to Crosspost include Bolney (1 mile north-east), Twineham Green (1 mile south), Twineham (2 miles south), Wineham (2 miles south-west) and Kent Street (2 miles west). Within a short drive, we also cover Crawley (9 miles north), Horsham (7 miles north-west), Worthing (14 miles south-west), Haywards Heath (5 miles east), Burgess Hill (4 miles south-east) and East Grinstead (13 miles north-east).
Near you in Crosspost
The closest station to Crosspost is Wivelsfield station, roughly 4.2 miles east. A little further out are The Dene Hospital (2.5 miles south-east) and Cuckfield Museum (3.2 miles north-east). Open spaces near Crosspost include Blunts Wood and Paiges Meadow.
The process
At the end, we look at the finished work together. The visit itself normally takes a morning for a couple of windows and a door, depending on how much there is to do. In a small place like Crosspost, access is normally the main thing to plan. For outside work, also let us know about exposed walls and any outbuildings involved.
- First, we go round the frames with you and agree the list.
- We remove the old mastic and clean the frame edge and wall.
- Where the gap is deep, backing rod goes in first.
- A flexible exterior sealant is applied in a colour to suit the frame.
- Every joint is tooled smooth and checked before we leave.
How to prepare
- For business premises, tell us about site rules or sign-in
- Keep pets and children clear of the area while we work
- Tell us if parking is tricky
Get a quote
We quote each job on its own. Just phone 0345 464 0079 or drop us an email with the details and send pictures if you have them.
Related advice
How we quote for window mastic
You’ll get a clear quote before work begins. It’s based on:
- Any working-time requirements on site
- The type of sealant required
- How much there is to do
- How much old sealant there is and how hard it is to remove
There are no prices on our website, because each job is priced on what it involves. Call for a quick quote and we’ll talk you through it.
Helping us quote
When you contact us, these details help:
- Any previous sealing or DIY work
- Where the property is
- Photos by email, if that’s easy
- How we’d reach the joints
We do not publish a price list, as no two jobs are quite the same. Instead, we give you a clear quote for your job. To arrange one, call 0345 464 0079 or drop us an email.